target/linux/bcm27xx/patches-5.4/950-0128-gpiolib-Don-t-prevent-IRQ-usage-of-output-GPIOs.patch

   1 From 122b21149cada59805040895f3d679ceb0e00063 Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.org>
   3 Date: Tue, 24 Apr 2018 14:42:27 +0100
   4 Subject: [PATCH] gpiolib: Don't prevent IRQ usage of output GPIOs
   5
   6 Upstream Linux deems using output GPIOs to generate IRQs as a bogus
   7 use case, even though the BCM2835 GPIO controller is capable of doing
   8 so. A number of users would like to make use of this facility, so
   9 disable the checks.
  10
  11 See: https://github.com/raspberrypi/linux/issues/2527
  12
  13 Signed-off-by: Phil Elwell <phil@raspberrypi.org>
  14 ---
  15  drivers/gpio/gpiolib.c | 8 +++++---
  16  1 file changed, 5 insertions(+), 3 deletions(-)
  17
  18 --- a/drivers/gpio/gpiolib.c
  19 +++ b/drivers/gpio/gpiolib.c
  20 @@ -55,6 +55,8 @@
  21  #define        extra_checks    0
  22  #endif
  23
  24 +#define dont_test_bit(b,d) (0)
  25 +
  26  /* Device and char device-related information */
  27  static DEFINE_IDA(gpio_ida);
  28  static dev_t gpio_devt;
  29 @@ -3091,8 +3093,8 @@ int gpiod_direction_output(struct gpio_d
  30                 value = !!value;
  31
  32         /* GPIOs used for enabled IRQs shall not be set as output */
  33 -       if (test_bit(FLAG_USED_AS_IRQ, &desc->flags) &&
  34 -           test_bit(FLAG_IRQ_IS_ENABLED, &desc->flags)) {
  35 +       if (dont_test_bit(FLAG_USED_AS_IRQ, &desc->flags) &&
  36 +           dont_test_bit(FLAG_IRQ_IS_ENABLED, &desc->flags)) {
  37                 gpiod_err(desc,
  38                           "%s: tried to set a GPIO tied to an IRQ as output\n",
  39                           __func__);
  40 @@ -3895,8 +3897,8 @@ int gpiochip_lock_as_irq(struct gpio_chi
  41         }
  42
  43         /* To be valid for IRQ the line needs to be input or open drain */
  44 -       if (test_bit(FLAG_IS_OUT, &desc->flags) &&
  45 -           !test_bit(FLAG_OPEN_DRAIN, &desc->flags)) {
  46 +       if (dont_test_bit(FLAG_IS_OUT, &desc->flags) &&
  47 +           !dont_test_bit(FLAG_OPEN_DRAIN, &desc->flags)) {
  48                 chip_err(chip,
  49                          "%s: tried to flag a GPIO set as output for IRQ\n",
  50                          __func__);